Monday, April 09, 2012

Flat Earth Kayak Sails Code Zero 0.8 long term test.

For the last six months I have been extensively testing the, soon to be released in UK, Flat Earth Kayak Sails Code Zero 0.8 m2 sail. I love it! Basically it comes along every time we go out.

Choice of sail size.
The Code Zero sails are available in 0.75, 0.8  and 1.0 m2. In the UK they are available from Karitek. We have used the 0.8  in winds up to the top of Force 5 and I think that 0.8m2 is the perfect size for NW Europe. The 1 m2 size is popular in Australia but there are differences in the wind there. We tend to get gusty low pressure winds while nearer the tropics, steady trade winds predominate. Also the density of the air is greater in cold dry conditions. When the above photo was taken the air temp was 5C and the humidity was 10% and the air density was 1.265kg/m3. 12 hours later, my brother in Melbourne experienced 38C and a humidity of 85% and the air density was 1.107, some 13% less. Since the force on a sail is directly proportional to the denisty of air and the square of the wind speed, for a given wind speed the force on the sail will be greater in cold dry air. In lochs and lakes the wind speed will be less than the open sea but as it will be gustier, I still think the 0.8 m2 is the most suitable size for NW Europe kayak sailing mostly in winds of Force 2 to 5.

The Code Zero has been tested  alongside FEKS classic line sails, both the Standard 0.8sqm with 18 degrees of twist in the head and...

...the later standard 0.8sqm with 12 degrees of twist. Comparative testing has been carried out on pairs of P&H Quest and P&H Cetus kayaks. 

I have also used it extensively on a Nordkapp LV and also the P&H Delphin, which has proved to be a particularly potent kayak sailer.

Design and construction.
The Code Zero 0.8 is made of a dacron, spectra scrim, mylar laminate that is resistant to stretching and has low water adsorption . It is only available in white. The cut is fuller than previous sails, with a further reduction in twist in the head. The outline shape of the Code Zero 0.8 has also hanged from the Standard 0.8 design. Basically the inverted triangle formed by the mast and the main batten remains the same but the boom is now angled more steeply up. The leech between the boom and the main batten has been extended to form a roach. This extra area is supported by two mini battens, which are sewn into the leech. Overall this has reduced the area low down on the sail and increased the area higher up. The longer chord provided by the roach has increased the power of this sail for the same sized mast and boom. It has also moved it higher up into cleaner air where the sail can be more efficient.

Choice of mast length.
Several people in Scotland and Australia have shortened the mast and brought the tack of the sail down to nearly deck level (a cut out in the luff is then necessary to attach the stays to the mast). The idea of this is to reduce the tipping force of the sail in stronger wind. In practice, this doesn't work efficiently as the sail is working in slower, disturbed wind near the waves. My friend John altered his Standard 0.8 rig in this way and last summer, we spent an interesting afternoon comparing his modified rig with my unmodified Standard 0.8 rig on a pair of Nordkapp LV's in lively force 4 to 5 conditions on the Solway.

Swapping between kayaks, we could not detect any difference in stability between the two rigs. Secondly, the higher rig performed significantly better on all points of sailing but especially when close reaching. John has now changed his rig back to the higher standard arrangement. (Another drawback of mounting the sail lower and attaching the stays through a cut out in the sail is that you cannot let the sheet right out and let the boom swing in front of the mast if you are overpowered on a run.)

Launching the new Code Zero sail you are immediately aware of the increase in power. In a F4 wind the Code Zero goes up with a Whumph rather than the more gentle Whuffffff of the standard sail. If you are launching downwind in lively conditions it is definitely worthwhile paddling hard to reduce the apparent wind before launching. I also find it easier to launch on a broad reach rather than dead down wind in stronger winds.
The Code Zero 0.8 takes a nice three dimensional aerofoil shape even in light winds. It definitly gets going quicker than the Standard sail in very light winds. However, rather surprisingly it does not point so high into the wind as the Standard sail in F2-3 winds. However, as the wind increases to F3-5, the Code Zero points significantly higher and travels faster than the standard sail when going up wind. Note the progressive twist in the sail from the clew to the head. The sail will point to about 68 degrees off the wind direction.

Here you can see the greater degree of twist in an early Standard sail. This does give a nice soft forgiving feeling and Phil's first experience of any sailing was with this sail in a F4 wind! He survived intact and was hooked! In a way I hope the standard sails will still be available for those that like colours and a softer more forgiving feel.

Expedition use.
I have also used the Code Zero on a fully loaded Cetus MV on a three day winter bothy expedition and a five day spring camping expedition. The loaded kayak obviously does not accelerate under sail power to the same extent as when day paddling. However, the help given by the sail at the end of a 44km day, when its getting dark and cold, has to be experienced to be fully appreciated!

Day use.
Last Sunday we paddled 14.5 km out to Ailsa Craig, an isolated island in the mouth of the Firth of Clyde. We paddled straight into a F3-4 wind and while we were on the island the wind increased to F4-5. I was using the Code Zero on a Cetus MV. We took off like scalded cats and the Code Zero behaved impecably even in the gusty conditions in the lee of Ailsa Craig. What followed was some of the finest sea kayaking fun we have ever had. Some 14km of exposure, the wind and the swell all added to the fun. The sails regularly allowed us to surf faster than the waves. Slicing up the back of a wave then surfing its front is incredible fun. We were regularly hitting 13km/hr and my maximum run was 18km/hr. At these speeds group control becomes more critical than our usual spread, so we paddled 3 abreast in tight formation and had our VHFs ready on channel 6 in case one needed to call for assistance from the others.

Finally, if you remain to be convinced, this short video shows the Code Zero 0.8 kayak sail in F4-5 winds along the cliffs of the south Ayrshire coast.

Wear and Tear.
The white material does show the dirt so it is worth keeping it clean. I have removed stains with a dilute solution of cold water and a few soap flakes. My sail has no signs of wear or delamination of the mylar backed material. The shape of the sail has not distorted with fairly extensive use. This has resolved my one quibble with the Standard sail. After extended use, the leech material can stretch a little and flutter.

After testing the standard sail, I said I was blown away by it. After testing the Code Zero, it would take a hurricane to get it out of my hands. It has become such an integral part of my paddling, I cannot now imagine sea kayaking without it.

See also.
Flat Earth Kayak Sails Code Zero 0.8, first review
Flat Earth Kayak Sails preview
Flat Earth Kayak Sails fitting instructions
Is it worth tacking upwind with a Flat Earth kayak Sail?
Sea kayak sailing for non sailors
Flat Earth Kayak Sailing Code Zero 0.8 production version test and review.

Conflict of interest statement.
I was the first person to import a FEKS into the UK. I have bought two Flat Earth Kayak Sails as a normal customer but I have also been given two sails free of charge by Mick MacRobb (the designer) for testing purposes (I had to pay UK import duty on the first). I have since given the first test sail (FoC) to a friend but I still have the use of the test Code Zero sail and lend it to others, such as Mike in the first photo above.


  1. Douglas, Im glad you approved of the test sail, im half way through filling the UK shipment of the first batch, Kariteck will have sume of the CZ100, CZ80 and the CZ70 arriving sune.
    the final design has changed a litel from the test sail, the baterns have been remooved and the roach taken out, on two of the other test sails we had problems with the baterns
    but on a hole the test sails have prooven good . as always your testing is good unbias and pricles.
    Mick MacRobb

    1. Hi Mick good to hear from you, as you can see we form a Flat Earth flotilla any time we go out now! :o)

  2. Hi Douglas thanks for another great review. I have been watching with interest as all your friends have one by one got sails. The time has now come for me to join the kayak sailors! I like the way that you declare any interest in the test items but from your track record of previous reviews I know you will tell it how it is. Some internet reviews are little more than adverts.

    Hope your knees are improving, Andy.:-)

    Cheers Andy

    1. Hi Andy, thank you. My knees are getting better but one gave way and I knocked one of my front teeth out two days before my daughter's wedding. Ouch.

  3. Douglas,

    How do you mount the mast on the plastic Delphin? Do you support the underside of the deck somehow?


    1. Hi KP the ridge on the Delphin deck makes it very stiff. I mount the mast foot just off centre two one side of the ridge. Purists are horrified but it makes absolutely no difference to the sailing and is a simple strong mount.

  4. Rob Matthews11/04/2012, 11:31

    Douglas - Thanks for an excellent and thorogh review. I believe that Kari-Tek are expecting the Code Zero sails sometime in July. I'll wait till then before buying with a view to fitting to my Quest. Can't wait - you've been an inspiration once again!

  5. Thank you Rob, the Code Zero works really well on my Quest LV.

  6. Hi! Are the code zero and the standard 0.8 easilly interchangable from sitting in the kayak?

    Also, how does flat earth compare to falcon sails? I have just read reviews and by them it seems the falcon is superior, but again, there are complaints about cheap plastic parts and less than ideal sailcloth. What is your take?

    1. Greetings Anders, firstly yes it is possible to change the Original, Code Zero and Tradewind sails while seated in the cockpit and afloat. All you would need to do would be to untie the sheet from below the boom on the sail you started with then retie the sheet to the replacement sail. The only reason for wanting to do this would be if you had two sizes of sail. Myself and several friends have FE sails in 1.0, 0.8 and 0.7 sqm sizes but in practice we only use the 0.8 sqm size, even in lighter winds.

      With regard to the Falcon sails being found to be superior in reviews... that is not my experience and I have owned and used both. They are very different sails. Falcons are much larger and have a tight leached cut. This makes them powerful but unforgiving in gusts and they obviously haver a lower high wind range than a smaller sail. I like Falcon Sails in light, steady winds in sheltered water. They are powerful enough not to require much paddle input. During the corona virus lockdowns, when I could not travel to the sea, I dug out the Falcon sail and had some very pleasant light wind days on our local reservoir. However, where I am based on the west coast of Scotland we mostly paddle on the sea and the prevailing SW winds come in from the Atlantic. On many of the days we paddle in, it is just too windy to launch the Falcon on open water. Sometimes, if it is very windy, we paddle in sheltered sea lochs (fjords) that are surrounded by mountains. Although the average wind speed may be less, you do get occasional violent gusts in these areas. The size and tight leach of the Falcon makes it unsuitable for handling gusty conditions compared with the smaller, loose leach of the FE. Another issue with the Falcon (and similar sized sails like the Kuvia Kayaksailor which I also have) in Scotland is that because you need to paddle less (while they are in their wind range) you get cold. That is also why we have settled on using the 0.8 sqm FE size, which is paddle sailing not just sitting there sailing!.

      I have not seen many Falcon sails in the UK. Most I have seen are fitted to wide stable recreational sit on top kayaks where their size and power is an advantage and the users are unlikely to take them far offshore into exposed waters. I only know of three people who have fitted Falcons to Sea kayaks and one of them is me!

      I have not used my Falcon rig enough to see any problems with the materials. Falcon say they use "the best cloth available", which is woven Dacron. FE sails used to be made of Dacron and customers like the choice of colour available with Dacron but kayak sailing is tough on sail cloth due to the repeated lowering, folding and raising the sail compared with a dinghy or yacht sail. Dacron cloth is coated with a resin to prevent the woven cloth stretching. This wears off with folding and then the sail stretches out of shape, especially at the leach. A friend's used Falcon sail is now like a shapeless bag and its controllability is not nearly so good as my lightly used one. FE moved to a more modern sail cloth, which is either a bi-laminate mylar (Code Zero) or tri-laminate (Tradewind and later). This ages much better than Dacron and the sail will maintain its shape and performance far longer than an all Dacron sail. However, all sail cloths will deteriorate with repeated folding. Some manufacturers (like KCS in Scotland) use Dacron in the luff panel and tri-laminate in the leach. The idea of this is that the softer luff panel will show signs of back winding earlier than a stiffer tri-laminate luff. This makes it easier to sail close to the wind but the leach will still be more resistant to wear and stretching.

      I hope that helps. :o)